Natural gas may be collected in a portable sample collection vessel and taken to a laboratory for analysis. This technique is often called “spot sampling” in the industry. In the laboratory, the sample is often analyzed to determine the Btu content of the natural gas using a high pressure gas chromatograph (HPGC). The HPGC is an excellent instrument for analyzing the content of a dry sample of any gas; however this instrument does not do a good job of analyzing a sample that includes fluids.
While spot sampling natural gas, it is important to determine whether the gas is dry or if it has entrained liquids, which is often referred to as “wet gas”. U.S. Pat. No. 6,818,045, which is incorporated herein by reference, entitled “Liquid Separator with Integral Sight Glass” assigned to Welker Engineering Company, the predecessor of the present assignee, Welker, Inc. was an apparatus that was intended to show whether the gas was dry or wet as it passed into a sample container during a spot sampling procedure. However, in use, it was difficult for the field technician to accurately determine whether the gas was dry or wet using the apparatus disclosed in the '045 Patent. There is still a need in the industry for an economical and simple way to determine whether gas is wet or dry while spot sampling.
Welker Engineering Company has previously sold a sight glass without a filter called the model SG3. The SG3 sight glass was primarily used with odorant injection systems to provide visual confirmation that the odorant was being properly injected into the system. The SG3 was also used to provide visual confirmation in chemical injection systems that use glycol. In some situations, the SG3 has been used at a spot sampling station to visually determine if liquid was being transferred into a sample cylinder. The SG3 did not prevent liquids from entering a sample cylinder nor did it have a flow directing assembly.
Welker, Inc. has also previously sold a filter without a sight glass called the LE2. The LE2 filter has been used at spot sampling stations to keep liquids out of sample cylinders. However, the LE2 filter did not provide any visual information to the personnel that were taking the spot sample.
Other companies, such as A+ Corporation of Prairieville, La. also sell liquid separators and filters to keep liquids out of sample cylinders at spot sampling stations. Some of these products from A+ are described in the company web site (www.apluscorporation.com), but none have a flow directing assembly. In summary, the prior art filters and liquid separators from Welker and A+ do not incorporate a sight glass or a flow directing element. There is still a need in the industry for improved equipment to detect entrained liquids in natural gas.